Attachment for party-line telephone systems.



.PATENTED NOV. 8, 1904.

W. A. SH-AGKBLFORD. ATTACHMENT FORIARTY LINE TELEPHONE SYSTEMS.

APPLICATION FILED DEC. 3, 1903.

3 SHBETB 5 BLT 1.

N0 MODEL.

O Q (NVEA'ITOH A fro/m5 rs No. 774,608. PATENTED NOV. 8, 1904.

' SHACKELFORD. ATTACHMENT FOR PARTY LINE TELEPHONE SYSTEMS.

APPLICATION rum) DEC. a. 1903. no MODEL. Q sums-SHEET 2.

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W. A. SHACKBLFORD. ATTACHMENT FOR PARTY LINE TELEPHONE SYSTEMS.

APPLICATION FILED DBO. 3. 1903.

3 SHEETS-SHEET a,

NO MODEL.

WITNESSES fil v 4 ATTORNEYS.

UNITED STATES Patented November 8 190 1.

, PATENT ()FFICE.

ATTACHMENT FOR PARTY-LINE TELEPHONE SYSTEMS- SPECIFIGATION forming part of Letters Patent No. 774,608, dated November 8, 1904.

Application filed December 3, 1903. Serial No- 183,6l1. (No model.)

To ztZl whom it may concern.-

Be it known that I, WVILLIAM ALSA SHACK- ELFORD, a citizen of the United States, and a resident of Lexington, inthe county of Oglethorpe and State of Georgia, have invented a new and Improved Attachment for Party- Line Telephone Systems, of which the following is a full, clear, and exact description.

My invention relates to telephony, my more particular object being to produce an attachment for party line telephone systems in which certain advantages are attained, among them being the following, to wit: First. Any subscriber, other than those engaged in conversation, is prevented from hearing the conversation between those using the line. Second. Several pairs of stations upon the same line may be in communication at the same time without interference with each other, the line being thus practically divided up into several circuits. Third. When two subscribers are talking, the lines are grounded (or metallic circuits completed according to the system used) upon either side of the two stations in active use, thus lessening the resistance of the circuits and improving the service.

Reference is to be had to the accompanying drawings, forming a part of this specification, in which similar characters of reference inclicate corresponding parts in all the figures.

Figure 1 is a diagram showing the partyline equipped with my invention, the instruments being in their several normal positions.

-- Fig. 2 is a somewhat similar diagram, but

showing the subscribers at stations 3 and 4: as holding conversation with each other. Fig. 3 is a front elevation, partly in section, of a portion of the outfit at each station. Fig. 1 is a vertical section upon the line L 4 of Fig. 3 looking in the direction of the arrow. Fig. 5 is a fragmentary elevation, partly in sec- "tion, on the line 5 5 in Fig. 3 of the localalarm mechanism for apprising other subscribers than those in the direction from which the line is grounded or the circuit is completed when a receiver is removed from the switchhook. Fig. 6 is a fragmentary plan view of the switch-hook, showing certain contact-springs in horizontal section on the line 6 6 in Fig. 4;

and Fig. 7 is a diagram, showing the attachment as used with a metallic return-circuit.

The attachment is shown more particularly in Figs. 3 and 6. Itconsists of a pivoted lever 15, a contactplate 22, a contact-plate 23, and a spring-contact member 53 with con- 'necting-wires, as hereinafter described, and a bell 24.

One form of apparatus, which may be used in connection with my attachment, is shown in Fig. 3. A bell -box 5 is provided with binding-posts 6, 7, 8, and 9 in the usual manner. The casing is also provided with hinges 1O 11 and with a ground-plate 12, a spring 13, and a line-plate 14, these parts constituting a lightning-arrester. Within the bell-box the lever 15 is pivoted at 16 and provided with a link 17, rigidly connected therewith. A flexible cord 18 is secured to the link 17 and may be used for drawing the lever downward in the position indicated in Fig. 4:. The lever 15 is provided with a stem 19, extending through a slot 21 in the box 5. and is provided with a head 20, by which the lever can be moved up and down from the outside of the bell-box. The contact-plate 22 is disposed above the lecommunicates with the spring-contact mem' ber 53, which is so placed as to make contact with the switch-hook when the receiver is raised.

A mechanical gong is shown at 24 and is provided with a clapper 25. This clapper is mounted upon a support 26, this support being normally held in position, as indicated in Fig. 5, by means of a spring 27, which engages a stationary boss 28. The support 26 is mounted upon a pivot 29 and is provided with a movable jaw 30, pivoted at 33 and engaged by a leaf-spring 31, rigidly connected upon the support 26. A pin 32 serves asa ver 15, and below the lever is the contactlimiting-stop for the support 26. The switchhook is shown at 34 and passes through a slot 35 in the casing, as shown in full lines in Figs. 3 and 5. The magneto 36 (see Figs. 1, 2, 3, and 7) is used for ringing in the usual manner and is provided with the ordinary accessories, including a revoluble armature 37, a gear-wheel 38, a shaft 39, a crank 40, and a handle 41. The gear-wheel 38 meshes with another gear-wheel, 43, mounted upon a shaft 44. This shaft is engaged by acontact-spring 45, as shown at the left of Fig. 3.

Beneath the switch-hook 34 is a leaf-spring 46, provided with a binding-post 47 and serving the double purpose of a resilient member and a conductor. The switch-hook is free to swing upon a pivot '48 and is provided with a claw 49, having a contact-surface 50. Disposed adjacent to the contact-surface 50 of the switclrhook are spring-contacts 51, 52, 53, and 54. 1 do not limit myself to the particular arrangement shown by these contacts. The pivot 48, supporting the switch-hook 34, is mounted upon an arm and is disposed adjacent to this arm, and crossing the same is a plate 56 of insulating material, preferably hard rubber. Another plate, 57, of insulating material, supports the contact members 51, 52, and 54. The contact-spring 54 is bent outwardly, as indicated in Fig. 3, and is moved to the left, as shown in that figure, when the switch-hook is moved downward or into its normal position. When, however, the switch-hook moves upward, or into its abnormal position, the spring-contact member 54 lodges against the partition 56, of insulating material, and the contact-surface 50 of the switchhook makes engagement with the spring-contact members 51 52, the last-mentioned contact member in turn engaging the contact member 53. It follows, therefore, that upon the upstroke of the switch-hook the spring-contact members 51, 52, and 53 are connected electrically together, whereas upon the downstroke of the switch-hook the three contact members are disengaged from each other and from the switch-hook and the springcontact member 54 is engaged by the switchhook. The contact member 54 is therefore a normal contact member, whereas the others are abnormal contact members.

When the ground-return system is used, the several stations are provided at 58 with ground-wires 59. Each station is provided with an electric bell 60, a local battery 61, a primary winding 62, and a transmitter 63, these parts being of ordinary construction. Each battery 61 is connected by a wire 64 with the abnormal contact member 52. Each abnormal contact member 51 is connected by a wire 65 with the primary winding 62 and with a secondary winding 66. This winding is also connected by a wire 67 with a receiver 68. This receiver is in turn connected with the line-wire 69. By means of a wire 70 the contact member 23 in each casing is conl of all other stations.

nected with the abnormal contact member 53. The contact member 22 in each casing is connected by a wire 71 with the line 69. The normal contact 54 is connected by a wire 72 with the electric bell 60 and the magneto-generator 36.

Where my attachment is used in connection with a circuit having a metallic return, as indicated in Fig. 7, the operation of the device is substantially the same as with the grounded circuit. In fact, my attachment may be used with systems of many different kinds and varying in details. In Fig. 7 the metallic return-wire is shown at 58, and the several wires 59, which take the place of the several ground-Wires in the other system, are connected directly with the wire 58.

The operation of my device is as follows: The normal positions of the several mechanisms are indicated in Fig. 1. It will be understood, of course, that the receivers 68 are hanging upon their respective switch-hooks 34 and that the abnormal contacts 54 are engaged by their respective switch-hooks 34. The line is now in condition for an alarm. If any subscriber actuates his magneto 36, the line is energized and over the following circuit: line 69, switch-hook 34, contact member 54, wire 72, electric bell 60, generator 36, wire 69 to next station, thence through switch-hook 34, normal contact 54, wire 72, electric bell 60, generator 36 to line 69, and so on throughout the series of stations. Suppose now that subscriber at station No. 4 has called subscriber at station N o. 3 and that said subscriber has answered. Subscriber at station No. 3 after removing his receiver in order to answer the call of subscriber No. 4 would. have to force the lever 15 upward by means of the button 20, as above explained. He would thereby ground or complete the circuit from subscriber at station No. 2 through wire 71, contact 22, lever 15, wire 59 to ground 58 or return-circuit wire. It is not necessary for the subscriber at station No. 4 to move the lever 15 in order to cut out stations to the right of station No. 4. The talking-circuit is now complete as between the two stations, but no further in either direction, and may be traced as follows: ground 58 (or return-circuit wire of metallic circuit) at station N o. 4, ground-wire 59, (or return-circuit wire,) lever 15, contact member 23, wire 7 0, switclrhook 34, contact member 51, wire 65, secondary winding 66, wire 67, receiver 68, wire 69 to station No. 3, switch-hook 34 at this station, contact member 51, wire 65, secondary winding 66, wire 67, receiver 68, wire 71, contact member 22, lever 15, ground-wire 59 to ground 58, (or returncircuit wire of metallic circuit.) The two stations 3 and 4 are thus each grounded, (or circuits between them completed,) so that a comparatively short talking-circuit is formed between these two stations and to the exclusion Similar circuits may be formed between any other two stations, provided these two stations are both upon the same side of such stations as may be already talking. The entire line may be thus broken up into pairs of stations holding conversation with each other, each pair being independent of the other pair. It now two subscribers say No. 2 and N o. a-are holding conversation with each other and No. 3 should remove his receiver 68, the circuit through No. 4 would be grounded (or completed through a metallic return) before reaching the transmitter and the receiver at station No. 3, it taking the following course: ground 58, (or metallic wire 58 at station No. 4,) ground-wire 59, lever 15, contact member 23, wire 70, contact member 53, switch-hook 3 1, contact member 51, wire 65, secondary winding 66, wire 67, receiver 68, wire 69 to station No. 3, thence through switch-hook 3 1 to contact 53, wire to contact 23, lever 15, (the lever now being down,) ground-wire 59 to ground 58, (or Wire 59 and metallic return 58*.) In this case station No. 1 could not be heard by an eavesdropper at station No. 3, nor could station No. 1 continue in conversation with No. 2. The instant subscriber No. 3 removes his receiver 68 the upstroke of the switch-hook 34: causes the support 26 (see Fig. 5) at his station to rise quickly upward, it being tilted so as to allow the switch-hook 34 to pass upward. This causes the clapper 25 to move out from the gong 24, and as soon as the switch-hook 34 is sufliciently elevated to release the support 26 the spring 27 thus causes the clapper to strike the gong forcibly. This occurs at the same instant or immediately after the engagement of the abnormal contacts 51, 52, and 53 by the switch-hook 34 at the station of subscriber No. 2. The result is that the clapper 25 strikes the gong 2 1 and makes a loud noise, which of course actuates the transmitter 61 at said station, causing it, through the agency of the primary winding 62 and the secondary winding 66, to send the sound of the gong over the line 69 to No. 2, apprising the subscriber at that station of the intrusion of an eavesdropper at station No. 3. The jaw 30 (see Fig. 5) being pivoted at 33 allows the switch-hook 34 to again assume its lowermost position, the jaw 30 merely tilting and being brought back to its normal position by virtue of the leaf-spring 31.

It will be noted that by the use of my attachment in connection with any of the wellknown systems the line-circuit may be greatly shortened as between two subscribers engaged in conversation, and all superfluous resistance is cut outthat is to say, when a given subscriber is talking with another subscriber the only resistance through which the talkingcurrents pass at the transmitting and receiving stations is the combined resistance of the instruments at the two stations and the two wires or the ground and the one wire conn'ecting these two stations. The etfic'iencyof the service is therefore greatly increased, and the talking is rendered much louder and clearer than is the case where my attachment is not used.

Having thus described my invention, I claim as new and desire to secure by Letters Patent 1. In a party-line telephone system,the combination with a transmitter, a receiver, and a movable switclrhook for normally supporting said receiver, of a local mechanical alarm controllable by movements of said switch-hook for producing a sound and thereby actuating said transmitter when said receiver is removed from said switch-hook.

2. In a party-line telephone system,the combination of a movable switch-hook, a normal contact member engaged thereby, a plurality of abnormal contact members to be engaged by said switch-hook when the same is disengaged from said normal contact member, separate lines connected respectively with said normal contact member and with said switchhook, a contact member connected with one of said abnormal contact members, another contact member connected with one of said lines, and means controllable at will for connecting either of said contact members with a return-circuit.

3. An attachment for party-line telephone systems, comprising a switch-lever provided with contacts connected respectively with a line, and with a return therefor, a movable switch-hook disposed adjacent to said lever, and a flexible cord connecting said switchhook and said lever together so that said lever may be actuated by movements of said switchhook.

4.. In an attachment for party-line telephone systems, the combination of a movable switch lever, contact members disposed upon opposite sides thereof and adapted to be engaged thereby, one of said contact members being connected with a lineand the other being connected with a return-circuit for said line, a switch-hook disposed adjacent to said lever and provided with contacts to be energized and deenergized by movements of said switchhook, and a flexible connection from said switch-hook to said lever for the purpose of actuating said lever by movements of-said switch-hook.

5. In an attachment for party-line telephone systems, the combination of a movable switchlever, contact members to be engaged thereby, a flexible cord engaging said lever, a switchhook engaging said flexible cord for pulling the same in one direction, and a manually-operated device for moving said lever in the opposite direction.

6. In an attachment forparty-line telephone systems, the combination of a switch-lever adapted to move in two opposite directions, contact members to be engaged by said lever and disposed upon opposite sides thereof, a

manually-operated member for moving said lever into engagement with one of said contact members, and mechanism connecting said lever with a switch-hook for moving said lever in the opposite direction.

7. In an attachment forparty-line telephone systems, the combination of a movable switchhook adapted to occupy elevated and depressed positions, a pair of abnormal contact members to be engaged by said switch-hook while in its upward position, one of said contact members being connected with the line, and mechanism connected with the other of said contact members and controllable at will for connecting and disconnecting the same with a return-circuit.

8. In an attachment for party-line telephone systems, the combination of a movable switchhook, a plurality of abnormal contact members to be engaged thereby, one of said contact members being permanently connected with the line, the other of said contact mem bers being connected with a switch, said switch being connected with a return-circuit, and mechanism connecting said switch and said switch-hook together so that said switch is controllable by movements of said switch-hook.

9. Inaparty-line telephone system,the combination of a plurality of outfits disposed at different stations, each outfitincluding a transmitter, a receiver, and a movable member for normally supporting said receiver, and a gong or equivalent sounding mechanism provided with a movable member to be disposed within the path of said movable member for producing a local sound and thus actuating said transmitter so as to send a warning over the 10. In a party-line telephone system, the combination of a plurality of station outfits disposed at separate stations and connected together, each outfit comprising a movable switch-hook and a mechanical alarm disposed adjacent to and actuated thereby for the purpose of indicating at other stations when the receiver at an intermediate station is removed from its switclrhook.

11.. In a party-line telephone system, the combination of a plurality of station outfits disposed at separate stations and connected together, each outfit comprising a transmitter,

a receiver, and a movable switch-hook for supporting said receiver, and a mechanical alarm disposed adjacent to the switch-hook and actuated thereby, for the purpose of indicating at other stations when one of said receivers at an intermediate station is removed from its switch-hook.

12. In a party-line telephone system, the combination of a movable switch-hook, lines connected therewith, mechanism provided with a lever free to move into diiferent relative positions for the purpose of separately establishing return-circuits to said lines, and a flexible connection extending from said lever to said switch-hook for moving said lever in one direction only.

13. In a party-line telephone system, the combination of a movable switch-hook, lines connected therewith, mechanism provided with a lever free to move into different relative positions for the purpose of separately establishing return-circuits to said line, and mechanism controllable by movements of said switch-hook for moving said lever in one direction only.

14:. In a party-line telephone system, the combination of a movable switch-hook, lines connected therewith, mechanism provided with a lever free to move into different relative positions for the purpose of establishing return-circuits for said lines separately, and a flexible connection between said lever and said switch-hook for the purpose of normally holding said lever in a predetermined normal position for grounding one of said lines.

15. An attachment for party-line telephone systems, comprising a movable switch-hook provided with a normal contact connected with the line and also provided with an abnormal contact, and a contact-lever connected with said switch-hook and movable thereby in one direction only for completing a circuit from said abnormal contact to said line when said switch-hook is depressed.

In testimony whereof I have signed my name to this specification in the presence of two su bscribing witnesses.

WILLIAM ALSA SHACKELFORD.

Witnesses:

T. G. LESTER, C. M. HUNTER. 

